The authors report six patients with acute endosulfan intoxication. The symptoms of nausea, vomiting, headache, and dizziness began 2.7 +/- 0.5 h after ingestion; in four cases the patients had been hospitalized but were asymptomatic. All had severe metabolic acidosis with high anion gap and hyperglycemia; five of six had decreased blood platelets. Three patients had pulmonary aspiration, and five required mechanical ventilation. The one fatality followed acute renal failure, disseminated intravascular coagulation, thrombi in the pulmonary arteries and aorta, and cardiogenic shock. In this patient the blood endosulfan was 2.85 mg/L versus a mean of 0.48 mg/L in the survivors.